Case study:Chelmer Valley Local Nature Reserve

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Project overview

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Status	Complete
Project web site
Themes	Habitat and biodiversity, Hydromorphology, Water quality
Country	England
Main contact forename	Matt
Main contact surname	Butcher
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Contact organisation web site
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Parent multi-site project
This is a parent project encompassing the following projects	No

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Project summary

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Restoration of the River Chelmer upstream of Chelmsford City Centre by re-profiling the banks to increase in-channel morphological diversity, create additional marginal aquatic habitats, improve floodplain connectivity and create additional backwater habitats. The River Chelmer has historically been heavily modified to improve flood protection and land drainage. This has led to a uniform wide, straight, deep channel upstream of Chelmsford City Centre. This in tern has resulted in reduced plant diversity, and there has recently been deterioration in fish status.

Monitoring surveys and results

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Increasing the diversity of the channel provide different habitats to support a wider diversity of plants and animals. Fish bays provide shallow, slower flowing, warmer water preferred by small fish and fry. Blackwater habitats increase habitat diversity, whilst providing a refuge for fish and invertebrates from high flows. The banks and channel of the main river were re-profiled at 9 locations. The river bank was lowered to re-connect the river to its natural floodplain, improving marginal and riparian wetland habitats. Improving connectivity between the river and floodplain allows sediment to settle out on the floodplain, and fish and invertebrates to escape from the highest flows in flood events By storing water on the floodplain sooner, downstream flood risk can also be reduced. The bank material was pushed into the channel, creating earth berms. These narrow the channel during low flows, increasing water velocity. This helps other river processes such as sediment transfer, erosion and depositing and oxygenation of the water, which creates habitats and improves water quality. The berms also create diversity of marginal and aquatic habitats, which was previously very uniform. In addition, shallow bays were created and a backwater improved to provide additional habitat for fish and fry.

Lessons learnt

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Early communication with permitting bodies and involvement of local communities is essential to deliver successful projects in a short timescale.

Image gallery

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Catchment and subcatchment Select a catchment/subcatchment Site Edit site Name WFD water body codes GB105037033950 WFD (national) typology WFD water body name Pre-project morphology Reference morphology Desired post project morphology Heavily modified water body No National/international site designation Local/regional site designations Protected species present No Invasive species present No Species of interest Dominant hydrology Dominant substrate River corridor land use Average bankfull channel width category Average bankfull channel width (m) Average bankfull channel depth category Average bankfull channel depth (m) Mean discharge category Mean annual discharge (m3/s) Average channel gradient category Average channel gradient Average unit stream power (W/m2) Project background Edit project background Reach length directly affected (m) Project started Works started Works completed Project completed Total cost category Total cost (k€) Benefit to cost ratio Funding sources Cost for project phases Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname Investigation and design more than 10000 k€ 2500025,000 k€ <br />25,000,000 € <br /> Stakeholder engagement and communication Works and works supervision Post-project management and maintenance Monitoring Reasons for river restoration Edit reasons for restoration Mitigation of a pressure Hydromorphology Biology Physico-chemical Other reasons for the project Measures Edit Measures Structural measures Bank/bed modifications Floodplain / River corridor Planform / Channel pattern Other Non-structural measures Management interventions Social measures (incl. engagement) Other Monitoring Hydromorphological quality elements Edit Hydromorphological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Biological quality elements Edit biological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Physico-chemical quality elements Edit Physico-chemical quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Any other monitoring, e.g. social, economic Edit Other responses Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Monitoring documents Upload monitoring documents Additional documents and videos Upload additional documents Additional links and references Edit links and references Link Description Supplementary Information Edit Supplementary Information